Age related changes in the characteristics of the near pupil response

Retinoscopes: Past and present

BACKGROUND

Retinoscopy is arguably the most important method in the eye clinic for diagnosing and managing refractive errors. Advantages of retinoscopy include its non-invasive nature, ability to assess patients of all ages, and usefulness in patients with limited cooperation or communication skills.

AIM

To discuss the history of retinoscopes and examine current literature on the subject.

METHODS

A search was conducted on the PubMed and with the reference citation analysis (https://www.referencecitationanalysis.com) database using the term "Retinoscopy," with a range restricted to the last 10 years (2013-2023). The search string algorithm was: "Retinoscopy" (MeSH Terms) OR "Retinoscopy" (All Fields) OR "Retinoscopes" (All Fields) AND [(All Fields) AND 2013: 2023 (pdat)].

RESULTS

This systematic review included a total of 286 records. Publications reviewed iterations of the retinoscope into autorefractors, infrared photo retinoscope, television retinoscopy, and the Wifi enabled digital retinoscope.

CONCLUSION

The retinoscope has evolved significantly since its discovery, with a significant improvement in its diagnostic capabilities. While it has advantages such as non-invasiveness and broad applicability, limitations exist, and the need for skilled interpretation remains. With ongoing research, including the integration of artificial intelligence, retinoscopy is expected to continue advancing and playing a vital role in eye care.

Ocular Accommodative and Pupillary Responses During Fixation on Augmented Reality With a Maxwellian Display

Purpose

This study aimed to investigate the changes in ocular refraction and pupillary diameter during fixation on augmented reality (AR) images using a Maxwellian display.

Methods

Twenty-two healthy young volunteers (average age, 20.7 ± 0.5 years) wore a Maxwellian display device in front of their right eye and fixated on an asterisk displayed on both a liquid-crystal display (real target) and a Maxwellian display (AR target) for 29 seconds (real as a baseline for 3 seconds, AR for 13 seconds, and real for 13 seconds) at distances of 5.0, 0.5, 0.33, and 0.2 meters. A binocular open-view autorefractometer was used to measure the ocular refraction and pupillary diameter of the left eye.

Results

Accommodative (5.0 meters, 0.28 ± 0.29 diopter [D]; 0.5 meter, -0.12 ± 0.35 D; 0.33 meter, -0.43 ± 0.57 D; 0.2 meter, -1.20 ± 0.82 D) and pupillary (5.0 meters, 0.07 ± 0.22 mm; 0.5 meter, -0.08 ± 0.17 mm; 0.33 meter, -0.16 ± 0.20 mm; 0.2 meter, -0.25 ± 0.24 mm) responses were negative when the real target distances were farther away. The accommodative response was significantly and positively correlated with the pupillary response during fixation on the AR target (R2 = 0.187, P < 0.001).

Conclusions

Fixating on AR images using a Maxwellian display induces accommodative and pupillary responses. Accommodative responses depend on the distance between real objects. Overall, the Maxwellian display does not completely eliminate accommodation in real space.

Glossiness perception and its pupillary response

Recent studies have revealed that pupillary response changes depend on perceptual factors such as subjective brightness caused by optical illusions and luminance. However, the manner in which the perceptual factor that is derived from the glossiness perception of object surfaces affects the pupillary response remains unclear. We investigated the relationship between the glossiness perception and pupillary response through a glossiness rating experiment that included recording the pupil diameter. We prepared general object images (original) and randomized images (shuffled) that comprised the same images with randomized small square regions as stimuli. The image features were controlled by matching the luminance histogram. The observers were asked to rate the perceived glossiness of the stimuli presented for 3,000 ms and the changes in their pupil diameters were recorded. Images with higher glossiness ratings constricted the pupil size more than those with lower glossiness ratings at the peak constriction of the pupillary responses during the stimulus duration. The linear mixed-effects model demonstrated that the glossiness rating, image category (original/shuffled), variance of the luminance histogram, and stimulus area were most effective in predicting the pupillary responses. These results suggest that the illusory brightness obtained by the image regions of high-glossiness objects, such as specular highlights, induce pupil constriction.

Introducing Dynamic Stimulation Aberrometry: Binocular Objective Accommodation versus Subjective Measures

Purpose

The objective measurement of binocular accommodation remains a challenge. The dynamic stimulation aberrometry (DSA) system uses wavefront measurements to dynamically assess accommodation. In this study, we sought to introduce this method in a large number of patients of varying age and compared it with the subjective push-up method as well as the historical results of Duane.

Design

This study is an evaluation of diagnostic technology.

Subjects

Ninety-one patients aged 20 to 67 years (70 healthy, phakic eyes and 21 myopic eyes after phakic intraocular lens implantation) were enrolled at a tertiary eye hospital.

Methods

All patients underwent DSA measurements; the accommodative amplitude of 13 patients chosen at random was additionally examined using the subjective push-up method introduced by Duane. DSA measurements were also compared with Duane's historical results.

Main Outcome Measures

Accommodative amplitude, dynamic parameters of accommodation, and near pupil motility.

Results

Dynamic stimulation aberrometry allowed objective measurement of binocular accommodation, which decreased with age (e.g., 30-39 years vs. > 50 years; 3.8 ± 0.9 diopters [D] and 0.1 ± 0.4 D, respectively). Dynamic parameters, such as time delay of the commencement of accommodation after near target presentation, increased with age (0.26 ± 0.14 seconds for 20-30 years vs. 0.43 ± 0.15 seconds for 40-50 years, P = 0.0002). The objective accommodative amplitude was significantly smaller than Duane's historic results (P = 0.001) as well as the subjective push-up method. Dynamic stimulation aberrometry records pupil motility dynamically in parallel to wavefront measurements. Maximum pupil motility during accommodation significantly decreased with age (P = 0.0002). Maximum pupillary speed did not correlate significantly with age.

Conclusions

Dynamic stimulation aberrometry allows objective, dynamic, binocular measurement of accommodation and pupil motility with high time resolution in subjects with accommodative amplitudes up to 7 D. This article introduces the method in a large study population and may serve as a control for further studies.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Using a video-based eye tracker to analyse the binocular near-reflex dynamics response

PURPOSE

This study presents a novel video-based eye-tracking system for analysing the dynamics of the binocular near-reflex response. The system enables the simultaneous measurement of convergence, divergence and pupillary size during accommodation and disaccommodation to aid the comprehensive understanding of the three-component near-reflex.

METHODS

A high-speed (90 Hz) video-based eye tracker was used to capture changes in eye gaze and pupil radius in 15 participants in response to altering stimulus conditions. An offline analysis involved separating the gaze vector components and pupil radius, which were fitted to a hyperbolic tangent function to characterise the dynamics of the near-reflex process.

RESULTS

Significant differences in the temporal parameters of the pupil radius were observed between the near-to-far and far-to-near vision changes, with faster miosis compared with mydriasis. Additionally, differences in response times were found between gaze angle components, with longer convergence times compared to changes in the vertical direction (saccades). The steady-state values of the gaze components and pupil radius were in line with theoretical expectations and previous reports.

CONCLUSIONS

The proposed system provides a non-invasive, portable and cost-effective method for evaluating near-reflex dynamics under natural viewing conditions using a video-based eye tracker. The sampling rate ensures the accurate assessment of vergence eye movements and pupillary dynamics. By simultaneously measuring eye convergence, divergence and pupil size, the system offers a more comprehensive assessment of the near-reflex response. This makes it a valuable tool for clinical diagnosis, research studies and investigating the effects of near work on the visual system.

Frequency dependence of coordinated pupil and eye movements for binocular disparity tracking

Introduction

Coordinated alignment of the eyes during gaze fixation and eye movements are an important component of normal visual function. We have previously described the coordinated behavior of convergence eye movements and pupillary responses using a 0.1  Hz binocular disparity-driven sine profile and a step profile. The goal of this publication is to further characterize ocular vergence-pupil size coordination over a wider range of frequencies of ocular disparity stimulation in normal subjects.

Methods

Binocular disparity stimulation is generated by presentation of independent targets to each eye on a virtual reality display, while eye movements and pupil size are measured by an embedded video-oculography system. This design allows us to study two complimentary analyses of this motion relationship. First, a macroscale analysis describes the vergence angle of the eyes in response to binocular disparity target movement and pupil area as a function of the observed vergence response. Second, a microscale analysis performs a piecewise linear decomposition of the vergence angle and pupil relationship to permit more nuanced findings.

Results

These analyses identified three main features of controlled coupling of pupil and convergence eye movements. First, a near response relationship operates with increasing prevalence during convergence (relative to the "baseline" angle); the coupling is higher with increased convergence in this range. Second, the prevalence of "near response"-type coupling decreases monotonically in the diverging direction; the decrease persists after the targets move (converge back) from maximum divergence toward the baseline positions, with a minimum prevalence of near response segments near the baseline target position. Third, an opposite polarity pupil response is infrequent, but tends to be more prevalent when the vergence angles are at maximum convergence or divergence for a sinusoidal binocular disparity task.

Discussion

We suggest that the latter response is an exploratory "range-validation" when binocular disparity is relatively constant. In a broader sense, these findings describe operating characteristics of the near response in normal subjects and form a basis for quantitative assessments of function in conditions such as convergence insufficiency and mild traumatic brain injury.

Baseline pupil size encodes task-related information and modulates the task-evoked response in a speech-in-noise task

Pupillometry data are commonly reported relative to a baseline value recorded in a controlled pre-task condition. In this study, the influence of the experimental design and the preparatory processing related to task difficulty on the baseline pupil size was investigated during a speech intelligibility in noise paradigm. Furthermore, the relationship between the baseline pupil size and the temporal dynamics of the pupil response was assessed. The analysis revealed strong effects of block presentation order, within-block sentence order and task difficulty on the baseline values. An interaction between signal-to-noise ratio and block order was found, indicating that baseline values reflect listener expectations arising from the order in which the different blocks were presented. Furthermore, the baseline pupil size was found to affect the slope, delay and curvature of the pupillary response as well as the peak pupil dilation. This suggests that baseline correction might be sufficient when reporting pupillometry results in terms of mean pupil dilation only, but not when a more complex characterization of the temporal dynamics of the response is considered. By clarifying which factors affect baseline pupil size and how baseline values interact with the task-evoked response, the results from the present study can contribute to a better interpretation of the pupillary response as a marker of cognitive processing.

Autonomic tone in children and adults: Pupillary, electrodermal and cardiac activity at rest

Considering the suspected involvement of the autonomic nervous system (ANS) in several neurodevelopmental disorders, a description of its tonus in typical populations and of its maturation between childhood and adulthood is necessary. We aimed to arrive at a better understanding of the maturation of the sympathetic (SNS) and parasympathetic (PNS) tonus by comparing children and adults at rest, via recordings of multiple ANS indices. We recorded simultaneously pupil diameter, electrodermal activity (EDA) and cardiac activity (RR interval and HRV: heart rate variability) in 29 children (6-12 years old) and 30 adults (20-42 years old) during a 5-min rest period. Children exhibited lower RR intervals, higher LF peak frequencies, and lower LF/HF (low frequency/high frequency) ratios compared to adults. Children also produced more spontaneous EDA peaks, reflected in a larger EDA AUC (area under the curve), in comparison with adults. Finally, children displayed a larger median pupil diameter and a higher pupillary hippus frequency than adults. Our results converged towards higher SNS and PNS tones in children compared to adults. Childhood would thus be characterized by a high autonomic tone, possibly reflecting a physiological state compatible with developmental acquisitions.

Affective Response Categories—Toward Personalized Reactions in Affect-Adaptive Tutoring Systems

Affect-adaptive tutoring systems detect the current emotional state of the learner and are capable of adequately responding by adapting the learning experience. Adaptations could be employed to manipulate the emotional state in a direction favorable to the learning process; for example, contextual help can be offered to mitigate frustration, or lesson plans can be accelerated to avoid boredom. Safety-critical situations, in which wrong decisions and behaviors can have fatal consequences, may particularly benefit from affect-adaptive tutoring systems, because accounting for affecting responses during training may help develop coping strategies and improve resilience. Effective adaptation, however, can only be accomplished when knowing which emotions benefit high learning performance in such systems. The results of preliminary studies indicate interindividual differences in the relationship between emotion and performance that require consideration by an affect-adaptive system. To that end, this article introduces the concept of Affective Response Categories (ARCs) that can be used to categorize learners based on their emotion-performance relationship. In an experimental study, N = 50 subjects (33% female, 19–57 years, M = 32.75, SD = 9.8) performed a simulated airspace surveillance task. Emotional valence was detected using facial expression analysis, and pupil diameters were used to indicate emotional arousal. A cluster analysis was performed to group subjects into ARCs based on their individual correlations of valence and performance as well as arousal and performance. Three different clusters were identified, one of which showed no correlations between emotion and performance. The performance of subjects in the other two clusters benefitted from negative arousal and differed only in the valence-performance correlation, which was positive or negative. Based on the identified clusters, the initial ARC model was revised. We then discuss the resulting model, outline future research, and derive implications for the larger context of the field of adaptive tutoring systems. Furthermore, potential benefits of the proposed concept are discussed and ethical issues are identified and addressed.

Lags and leads of accommodation in humans: Fact or fiction?

The focusing response of the human eye — accommodation — exhibits errors known as lags and leads. Lags occur when the stimulus is near and the eye appears to focus farther than the stimulus. Leads occur with far stimuli where the eye appears to focus nearer than the stimulus. We used objective and subjective measures simultaneously to determine where the eye is best focused. The objective measures were made with a wavefront sensor and an autorefractor, both of which analyze light reflected from the retina. These measures exhibited typical accommodative errors, mostly lags. The subjective measure was visual acuity, which of course depends not only on the eye's optics but also on photoreception and neural processing of the retinal image. The subjective measure revealed much smaller errors. Acuity was maximized at or very close to the distance of the accommodative stimulus. Thus, accommodation is accurate in terms of maximizing visual performance.

Pupillary light response after cataract surgery in healthy patients

PURPOSE

To examine the changes in the pupillary light response after phacoemulsification and to compare the difference in the response among patients in different age categories.

STUDY DESIGN

Prospective observational study.

METHODS

Four-hundred twenty-two eyes of 422 patients in 3 age categories (60-69 years, 70-79 years, and 80-89 years) scheduled for phacoemulsification were consecutively enrolled. The eyes underwent examinations with an infrared pupillometer to obtain the parameters of the pupillary light response preoperatively and at 1 day and 1 and 3 months postoperatively. Differences in the parameters of the pupillary response were compared among 4 time intervals and the 3 age categories.

RESULTS

The mean maximum and minimum pupillary diameters significantly decreased at 1 day postoperatively and returned to the preoperative level by 1 month postoperatively (P<.0001). The mean percentage of pupillary constriction was significantly reduced at 1 and 3 months postoperatively compared with preoperatively and at 1 day postoperatively (P<.0001). The average pupillary constriction and dilation velocities were significantly lower at 1 and 3 months postoperatively than they were preoperatively and at 1 day postoperatively (P<.0001). The latency to constriction did not differ significantly among the time intervals. The percentage of pupillary constriction was significantly smaller, and the average constriction and dilation velocities were lower in association with higher age categories at all time intervals (P≤.0185).

CONCLUSION

The pupillary light response was impaired several months after cataract surgery and worsened with increasing patient age, indicating that cataract surgery may compromise the pupillary constriction and dilation functions in association with age.

Visual outcomes in hyperopic myopic and emmetropic patients with customized aspheric ablation (Q factor) and micro-monovision

PURPOSE

To evaluate the visual outcomes, visual performance, and stereoacuity in presbyopic patients following treatment by a change in the corneal asphericity and micro-monovision.

METHODS

Presbyopic patients with diverse refractive errors and emmetropes (n = 30 eyes) were treated with a custom Q-ablation profile and micro-monovision in the non-dominant eye. There with a difference of Q - 0.30 in the Q profiles between dominant and non-dominant eyes. Patients were assigned in two groups based on the preoperative spherical equivalent (Group 1  + 4.00 to + 0.50, and group 2 neutral to - 3.00). Binocular uncorrected distance visual acuity (binocular UCVA), best-corrected visual acuity (BCVA), binocular uncorrected near visual acuity (binocular UNVA) preoperative and postoperative, spherical equivalent refraction, contrast sensitivity, and stereopsis were analyzed at 1, 3, and 6 months.

RESULTS

The mean age was 52.6 ± 5.1 (SD) years. At six months post-operation, the mean binocular uncorrected distance visual acuity (binocular UDVA) was 0.15 ± 0.04 logMAR (20/25-) in group 1, and 0.11 ± 0.05 logMAR (20/25) in group 2, and binocular uncorrected near vision UNVA was 0.5 ± 0.1 M (20/25 J2) in group 1 and 0.45 ± 0.2 M (20/25 J2) group 2. An increase in stereoacuity was found in both groups.

CONCLUSIONS

The correction of refractive defects using customized corneal asphericity was an effective treatment in presbyopic patients. Furthermore, the treatment was well tolerated in this group of patients. Following surgery, the quality of vision was adequate, and the stereovision improved in this cohort of patients.

Is accommodation a confounder in pupillometry research?

Much psychological research uses pupil diameter measurements to investigate the cognitive and emotional effects of visual stimuli. A potential problem is that accommodating at a nearby point causes the pupil to constrict. This study examined to what extent accommodation is a confounder in pupillometry research. Participants solved multiplication problems at different distances (Experiment 1) and looked at line drawings with different monocular depth cues (Experiment 2) while their pupil diameter, refraction, and vergence angle were recorded using a photorefractor. Experiment 1 showed that the pupils dilated while performing the multiplications, for all presentation distances. Pupillary constriction due to accommodation was not strong enough to override pupil dilation due to cognitive load. Experiment 2 showed that monocular depth cues caused a small shift in refraction in the expected direction. We conclude that, for the young student sample we used, pupil diameter measurements are not substantially affected by accommodation.

Pupil response is modulated with optokinetic nystagmus in transparent motion

When two visual patterns moving in opposite directions are superimposed on the same depth plane, they appear to have two transparent surfaces moving independently (transparent motion). Additionally, the direction of the slow phase of optokinetic nystagmus (OKN) corresponds to the direction of motion that dominates the perceptual appearance. This study examines whether pupil changes correspond to the luminance of the dominated objects related to the transition of the slow-phase direction in OKN following objects. Stimuli consisted of two random dot patterns of different luminance that moved in opposite directions. The results showed that pupil size changed in accordance with the luminance of the pattern in the slow phase of OKN immediately after OKN transition. This suggests that pupil size is modulated with OKN in transparent motion.

Difference in Pupillary Diameter as an Important Factor for Evaluating Amplitude of Accommodation: A Prospective Observational Study

Presbyopia is increasing globally due to aging and the widespread use of visual display terminals. Presbyopia is a decrease in the eye's amplitude of accommodation (AA) due to loss of crystalline lens elasticity. AA differs widely among individuals. We aimed to determine the factors that cause presbyopia, other than advanced age, for early medical intervention. We examined 95 eyes of 95 healthy volunteers (33 men, 62 women) aged 22-62 years (mean: 37.22 ± 9.77 years) with a corrected visual acuity of ≥1.0 and without other eye afflictions except ametropia. Subjective refraction, AA, maximum and minimum pupillary diameters during accommodation, axial length of the eye, and crystalline lens thickness were measured. AA was measured using an auto refractometer/keratometer/tonometer/pachymeter. The difference between maximum and minimum pupillary diameters was calculated. On multiple regression analysis, age and difference in pupillary diameter were both significantly and independently associated with AA in participants aged <44 years, but not in those aged ≥45 years. Our results suggest that the difference in pupillary diameter could be an important age-independent factor for evaluating AA in healthy individuals without cataract. Thus, improving the difference in pupillary diameter values could be an early treatment target for presbyopia.

Crowding in depth for binocular and monocular observation

Crowding refers to the phenomenon of reduced recognition performance for peripherally presented targets that are flanked by similar stimuli. Crowding is known to vary with lateral distances (i.e., effects of target eccentricity and inter-character spacing). In the present experiment, we examined how crowding is affected by the distance of the stimuli in depth for natural viewing, i.e., for binocular observation of a real depth presentation. Superimposing the displays of two orthogonally arranged screens with a half-transparent mirror created real-depth presentation. We measured recognition performance of flanked compared to isolated targets that were presented at fixation depth, or in depths deviating from fixation depth (defocused). For both defocused directions (i.e., in front of and behind fixation depth), a near as well as a far distance from fixation was applied. Participants' task was to fixate a central cross at a constant distance (190 cm), and to indicate the gap position of an isolated or flanked Landolt ring that was presented at an eccentricity of 2°, on, in front of, or behind fixation depth. Results for natural binocular observation revealed increased crowding effects when stimuli were far compared to near from the fixation plane in depth. This resembles the common effect of eccentricity. Under monocular viewing, that is, without disparity information, crowding did not increase with increased depth distance. Thus, the result seemed to be an effect of binocular observation in real depth. This suggests that crowding in natural viewing might serve as a mechanism to stabilize and orient attention efficiently in three-dimensional space.

Pupil Function in Pseudophakia: Proximal Miosis Behavior and Optical Influence

The pseudophakic eye lacks the ability to produce a refractive change in response to object proximity. Thus, individual anatomical features such as the pupil size play an important role in achieving functional vision levels. In this work, the range of pupil sizes at varying object distance was measured in pseudophakic participants. Furthermore, the impact of the measured values on eye optical quality was investigated using a computer simulation model. A binocular eye-tracker was used to measure the participants’ pupil sizes at six object distances, ranging from 0.33 m (i.e., vergence of 3.00 D) to 3.00 m (i.e., vergence of 0.33 D), while observing a Maltese cross with a constant angular size of 1 ∘ . In total, 58 pseudophakic participants were enrolled in this study (age mean ± standard deviation: 70.5 ± 11.3 years). The effects of object distance and age on pupil size variation were investigated using linear mixed effects regression models. Age was found to have a small contribution to individual variability. The mean infinite distance pupil size (intercept) was 4.45 ( 95 % CI: 2.74, 6.17) mm and the mean proximal miosis (slope) was − 0.23 ( 95 % CI: −0.53, 0.08) mm/D. The visual acuity (VA) estimation for a distant object ranged from − 0.1 logMAR (smallest pupil) to 0.04 logMAR (largest pupil) and the near VA ( 0.33 m) when mean proximal miosis was considered ranged from 0.28 logMAR (smallest pupil) to 0.42 logMAR (largest pupil). When mean distance pupil was considered, proximal miosis individual variability produced a variation of 0.04 logMAR for the near object and negligible variation for the distant object. These results support the importance of distance pupil size measurement for the prediction of visual performance in pseudophakia, while suggesting that proximal miosis has a negligible impact in VA variability.

Influence of refractive error on pupil diameters in highly myopic eyes with implantable collamer lenses

PURPOSE

To investigate the influence of refractive error on pupil diameters in highly myopic eyes with implantable collamer lenses.

SETTING

Shanghai, China.

DESIGN

A prospective consecutive observational study.

METHODS

Sixty-six eyes of 66 patients that underwent ICL V4c implantation were included. Pupil diameters before and 1 week, 1 month, and 3 months after surgery were measured using an automatic pupillometry system (MonCv3; Metrovision, Pérenchies, France) under four standardized illumination conditions: 0, 1, 10, and 100 cd/m². The correlations between changes in pupil diameter and spherical equivalent values and patient age were investigated.

RESULTS

Based on preoperative spherical equivalent values, included eyes were divided into a high-myopia group (-6.3 to -9.9 D (diopters)) and a super-high-myopia group (-10 to -20 D). Pupil sizes remained unchanged after surgery in the high-myopia group and decreased at 1 and 10 cd/m² in the super-high-myopia group. A between-group comparison showed that pupils were significantly smaller in the super-high-myopia group 1 week postoperatively under all illumination conditions and remained smaller at 1 month and 3 months under 1 and 10 cd/m² lighting conditions. Preoperative spherical equivalent values were significantly correlated with the percent decrease in pupil diameter 1 week postoperatively under 0, 1, and 10 cd/m² illumination conditions; the greater the degree of myopia, the greater the reduction in pupil diameter.

CONCLUSION

Preoperative refractive error significantly affects pupil diameter in highly myopic eyes after implantable collamer lens implantation. Pupils of super highly myopic eyes remained smaller than preoperative levels under mesopic conditions after implantable collamer lens implantation.

The influence of age, refractive error, visual demand and lighting conditions on accommodative ability in Malay children and adults

PURPOSE

Near work, accommodative inaccuracy and ambient lighting conditions have all been implicated in the development of myopia. However, differences in accommodative responses with age and refractive error under different visual conditions remain unclear. This study explores differences in accommodative ability and refractive error with exposure to differing ambient illumination and visual demands in Malay schoolchildren and adults.

METHODS

Sixty young adults (21-25 years) and 60 schoolchildren (8-12 years) were recruited. Accommodative lag and accommodative fluctuations at far (6 m) and near (25 cm) were measured using the Grand Seiko WAM-5500 open-field autorefractor. The effects of mesopic room illumination on accommodation were also investigated.

RESULTS

Repeated-measures ANOVA indicated that accommodative lag at far and near differed significantly between schoolchildren and young adults [F(1.219, 35.354) = 11.857, p < 0.05]. Post hoc tests using the Bonferroni correction showed that at near, there was a greater lag in schoolchildren (0.486 ± 0.181 D) than young adults (0.259 ± 0.209 D, p < 0.05). Repeated-measures ANOVA also revealed that accommodative lag at near demands differed statistically between the non-myopic and myopic groups in young adults and schoolchildren [F(3.107, 31.431) = 12.187, p < 0.05]. Post hoc tests with Bonferroni correction showed that accommodative lag at near was significantly greater in myopic schoolchildren (0.655 ± 0.198 D) than in non-myopic schoolchildren (0.202 ± 0.141 D, p < 0.05) and myopic young adults (0.316 ± 0.172 D, p < 0.05), but no significant difference was found between myopic young adults (0.316 ± 0.172 D) and non-myopic young adults (0.242 ± 0.126 D, p > 0.05). Accommodative lag and fluctuations were greater under mesopic room conditions for all ages [all p < 0.05].

CONCLUSION

Greater accommodative lag was found in myopes than in emmetropes, in schoolchildren than in adults, and under mesopic conditions than under photopic conditions. Accommodative fluctuations were greatest in myopes and in mesopic conditions. These results suggest that differences exist in the amount of blur experienced by myopes and non-myopes at different ages and under different lighting conditions.

Monovision Versus Multifocality for Presbyopia: Systematic Review and Meta-Analysis of Randomized Controlled Trials

INTRODUCTION

Refractive surgery in presbyopia tends to achieve spectacle independence with minimal optical disturbances. We compared monovision to multifocality procedures regarding these outcomes.

METHODS

We conducted a systematic review of published (till November 21, 2016) randomized controlled trials (RCTs) comparing any monovision to any multifocality method or comparing different monovision/multifocality methods to each other that enabled direct or indirect comparisons between particular monovision and particular multifocality procedures in presbyopic patients undergoing cataract-related or unrelated surgery in respect to spectacle independence, unaided binocular visual acuity (VA), contrast sensitivity (CS), and adverse events.

RESULTS

Three trials comparing monovision (monofocal lenses, LASIK) to multifocal intraocular lenses (MFIOLs; Isert refractive or Tecnis diffractive) and 6 comparing other MFIOLs to Tecnis were included (1-12 months duration). Spectacle independence. All reporting trials were of sufficient quality. Directly, pseudophakic monovision was inferior to Isert (1 trial, N = 75, RR = 0.49, 95% CI 0.28-0.80) and Tecnis (1 trial, N = 211, RR = 0.36, 95% CI 0.25-0.52) in cataract patients, and LASIK was comparable to Tecnis (1 trial, N = 100, RR = 0.93, 0.78-1.10) in refractive surgery. In network meta-regression (6 trials, 14 arms) pseudophakic monovision in cataract patients was inferior to Tecnis. Indirect data suggest also that it is inferior (ReZoom refractive, TwinSet diffractive) or tends to be inferior (Array refractive) to other MFIOLs. LASIK was comparable to Tecnis in refractive surgery. Indirect data suggest also that it tends to superiority vs. ReZoom or Array refractive MFIOLs. Adverse events. No pooling was possible (heterogeneity of assessment and reporting). One quality direct RCT indicated less glare/dazzle with pseudophakic monovision vs. Tecnis in cataract patients. Unaided VA and CS data were burdened with heterogeneity (assessment, reporting) and insufficient quality.

CONCLUSIONS

Randomized comparisons of monovision to multifocality are scarce. Existing estimates regarding spectacle independence (imprecision, indirectness) and particularly regarding unaided VA and CS (assessment/reporting heterogeneity, bias, imprecision, indirectness) are burdened with uncertainty. Dysphotopsia is less common with monovision, but estimate uncertainty is high (bias, imprecision).

Suitability of open-field autorefractors as pupillometers and instrument design effects

AIM

To determine the agreement and repeatability of the pupil measurement obtained with VIP-200 (Neuroptics), PowerRef II (Plusoptix), WAM-5500 (Grand Seiko) and study the effects of instrument design on pupillometry.

METHODS

Forty patients were measured twice in low, mid and high mesopic. Repeatability was analyzed with the within-subject standard deviation (Sw) and paired t-tests. Agreement was studied with Bland-Altman plots and repeated measures ANOVA. Instrument design analysis consisted on measuring pupil size with PowerRef II simulating monocular and binocular conditions as well as with proximity cues and without proximity cues.

RESULTS

The mean difference (±standard deviation) between test-retest for low, mid and high mesopic conditions were, respectively: -0.09 (±0.16), -0.05 (±0.18) and -0.08 (±0.23) mm for Neuroptics, -0.05 (±0.17), -0.12 (±0.23) and -0.17 (±0.34) mm for WAM-5500, -0.04 (±0.27), -0.13 (±0.37) and -0.11 (±0.28) mm for PowerRef II. Regarding agreement with Neuroptics, the mean difference for low, mid and high mesopic conditions were, respectively: -0.48 (±0.35), -0.83 (±0.52) and -0.38 (±0.56) mm for WAM-5500, -0.28 (±0.56), -0.70 (±0.55) and -0.61 (±0.54) mm for PowerRef II. The mean difference of binocular minus monocular pupil measurements was: -0.83 (±0.87) mm; and with proximity cues minus without proximity cues was: -0.30 (±0.77) mm.

CONCLUSION

All the instruments show similar repeat-ability. In all illumination conditions, agreement of Neuroptics with WAM-5500 and PowerRef II is not good enough, which can be partially induced due to their open field design.

Effects of multifocal soft contact lenses used to slow myopia progression on quality of vision in young adults

PURPOSE

To assess the effects of multifocal soft contact lenses (MF SCLs) used for myopia control on visual acuity (VA) and subjective quality of vision.

METHODS

Twenty-four young adult myopes had baseline high and low-contrast VAs and refractions measured and quality of vision assessed by the Quality of Vision (QoV) questionnaire with single vision SCLs. Additional VA and QoV questionnaire data were collected immediately after subjects were fitted with Proclear MF SCLs and again after a 2-week adaptation period of daily lens wear. Data were collected for two MF SCL designs, incorporating +1.50 and +3.00 D peripheral near additions, with a week washout period allowed between the two lens trials.

RESULTS

High- and low-contrast VAs were initially reduced with both MF SCL designs, but subsequently improved to be not significantly reduced in the case of high-contrast VA by the end of the 2-week adaptation period. The quality of vision was also reduced, more so with the +3.00 D MF SCL. Quality of Vision (QoV) scores describing frequency, severity and bothersome nature of visual symptoms indicated symptoms worsening rather than resolving over the 2-week period, particularly so with the +3.00 D MF SCL.

CONCLUSION

Low and high add MF SCLs adversely affected vision on initial insertion, with sustained effects on low-contrast VA and QoV scores but not high-contrast VA. Thus, high-contrast VA is not a suitable surrogate for quality of vision. In prescribing MF SCLs for myopia control, clinicians should educate patients about these effects on vision.

Prediction of accommodative optical response in prepresbyopic subjects using ultrasound biomicroscopy

PURPOSE

To determine whether relatively low-resolution ultrasound biomicroscopy (UBM) can be used to predict the accommodative optical response in prepresbyopic eyes as well as in a previous study of young phakic subjects, despite lower accommodative amplitudes.

SETTING

College of Optometry, University of Houston, Houston, USA.

DESIGN

Observational cross-sectional study.

METHODS

Static accommodative optical response was measured with infrared photorefraction and an autorefractor (WR-5100K) in subjects aged 36 to 46 years. A 35 MHz UBM device (Vumax, Sonomed Escalon) was used to image the left eye, while the right eye viewed accommodative stimuli. Custom-developed Matlab image-analysis software was used to perform automated analysis of UBM images to measure the ocular biometry parameters. The accommodative optical response was predicted from biometry parameters using linear regression, 95% confidence intervals (CIs), and 95% prediction intervals.

RESULTS

The study evaluated 25 subjects. Per-diopter (D) accommodative changes in anterior chamber depth (ACD), lens thickness, anterior and posterior lens radii of curvature, and anterior segment length were similar to previous values from young subjects. The standard deviations (SDs) of accommodative optical response predicted from linear regressions for UBM-measured biometry parameters were ACD, 0.15 D; lens thickness, 0.25 D; anterior lens radii of curvature, 0.09 D; posterior lens radii of curvature, 0.37 D; and anterior segment length, 0.42 D.

CONCLUSIONS

Ultrasound biomicroscopy parameters can, on average, predict accommodative optical responses with SDs of less than 0.55 D using linear regressions and 95% CIs. Ultrasound biomicroscopy can be used to visualize and quantify accommodative biometric changes and predict accommodative optical response in prepresbyopic eyes.

Visual Performance After Contralateral Implantation of Multifocal Intraocular Lenses With +3.0 and +4.0 Diopter Additions

PURPOSE

To evaluate visual performance after contralateral implantation of AcrySof ReSTOR aspheric intraocular lenses (IOLs) with +3.0 and +4.0 diopter near additions.

DESIGN

This was a retrospective case study conducted at Tokyo Dental College Suidobashi Hospital in Tokyo, Japan.

METHODS

Eleven patients who were implanted with the SN6AD1 IOL and the SN6AD3 IOL contralaterally were included in this study. The distance, intermediate (1 m, 50 cm), and near (40 and 30 cm) uncorrected and corrected binocular visual acuity (VA), contrast sensitivity, depth of focus, and patient satisfaction were assessed more than 1 month postoperatively.

RESULTS

Postoperatively, the mean uncorrected (corrected) binocular logarithm of the minimum angle of resolution VA levels were as follows: distance, -0.120 (-0.163); intermediate, 1 m, 0.226 (0.012) and 50 cm, 0.037 (0.006); and near, 40 cm, 0.067 (-0.040) and 30 cm, 0.091 (-0.053). The depth of focus had a smooth curve with double peaks. The mean contrast sensitivity was normal at all spatial frequencies. All patients were spectacle independent and expressed high satisfaction.

CONCLUSIONS

Contralateral implantation of multifocal IOLs with +3.0 and +4.0 D additions takes advantage of the good uncorrected near VA provided by both IOLs and may be an option for patients who require a broader range of good uncorrected near VA.

Pupil Diameter Changes in High Myopes after Collamer Lens Implantation

PURPOSE

To observe the changes in pupil size under photopic and scotopic conditions after Implantable Collamer Lens (ICL) implantations in eyes with high myopia.

METHODS

The ICL was implanted in 90 eyes belonging to 45 patients with high myopia. Photopic pupil diameters, scotopic pupil diameters, anterior chamber depths, and ICL vaults were examined at the preoperative, postoperative 1-month, and postoperative 3-month stages. The preoperative and postoperative photopic pupil diameters and scotopic pupil diameters were also compared with each other to note the differences between them. The correlations between preoperative and postoperative pupil diameter changes under different light conditions and presurgical refractive error were analyzed alongside patient's age and ICL vault.

RESULTS

Pupil diameters at both postoperative 1-month and postoperative 3-month stages were smaller than those before operation in distinct light environments, as well as pupil constriction amplitude. Correlation analysis showed that there was a statistically significant correlation between pupil diameter changes under different light conditions and presurgical refractive error at 1 month and 3 months after ICL implantation; pupil diameter decreased more when presurgical refractive error powers were less myopic. Statistically significant correlations were not found, however, with patient's age and ICL vault. Postoperative 1-month and mean postoperative 3-month anterior chamber depths were decreased when compared with preoperative anterior chamber depths. Statistically significant correlations were found in change in preoperative and postoperative anterior chamber depth and ICL vault. No statistically significant difference was found between ICL vault at the postoperative 1-month and postoperative 3-month stages.

CONCLUSIONS

Pupil diameter may decrease at the 1- and 3-month stages after ICL implantation under both photopic and scotopic conditions. This indicates that reduction of pupil diameter may be caused by mechanical contact between the ICL and the posterior iris surface.

Changes in the objective amplitude of accommodation with pupil size

PURPOSE

We evaluate the effect of pupil size on objectively measured amplitude of accommodation (AA).

METHODS

Pupil diameter and wavefront aberrometry were obtained in 15 eyes when stimulus swept across the range of clear vision in steps of 0.5 diopters. Wavefront refraction techniques were used to compute objective AA as the maximum refractive change. Measurements were obtained monocularly under low and high ambient room lighting conditions with a fixed luminance of the fixation target. Amplitude of accommodation computations were performed taking into account just paraxial rays (paraxial AA) or including the effects of the change of spherical aberration during accommodation (minRMS AA).

RESULTS

Mean pupil size values at low light level were 6.26 mm (relaxed) and 4.15 mm (maximum accommodation), whereas at the high light level, those values became 4.74 and 3.04 mm, respectively. The effects of both light level on accommodation were significant (p < 0.001), and accommodative miosis was slightly larger at low light levels. Mean minRMS and paraxial AA were always greater by more than 1 diopter in high than in low ambient lighting conditions (p < 0.01), indicating a significant impact of pupil size on AA.

CONCLUSIONS

The influence of the ambient lighting on the objective AA is not only attributed to the increased effects of spherical aberration as the pupil dilates but mostly attributed to a decrease in the paraxial accommodation as pupil dilates.

Clear-cornea cataract surgery: pupil size and shape changes, along with anterior chamber volume and depth changes. A Scheimpflug imaging study

PURPOSE

To investigate, by high-precision digital analysis of data provided by Scheimpflug imaging, changes in pupil size and shape and anterior chamber (AC) parameters following cataract surgery.

PATIENTS AND METHODS

The study group (86 eyes, patient age 70.58±10.33 years) was subjected to cataract removal surgery with in-the-bag intraocular lens implantation (pseudophakic). A control group of 75 healthy eyes (patient age 51.14±16.27 years) was employed for comparison. Scheimpflug imaging (preoperatively and 3 months postoperatively) was employed to investigate central corneal thickness, AC depth, and AC volume. In addition, by digitally analyzing the black-and-white dotted line pupil edge marking in the Scheimpflug "large maps," the horizontal and vertical pupil diameters were individually measured and the pupil eccentricity was calculated. The correlations between AC depth and pupil shape parameters versus patient age, as well as the postoperative AC and pupil size and shape changes, were investigated.

RESULTS

Compared to preoperative measurements, AC depth and AC volume of the pseudophakic eyes increased by 0.99±0.46 mm (39%; P<0.001) and 43.57±24.59 mm(3) (36%; P<0.001), respectively. Pupil size analysis showed that the horizontal pupil diameter was reduced by -0.27±0.22 mm (-9.7%; P=0.001) and the vertical pupil diameter was reduced by -0.32±0.24 mm (-11%; P<0.001). Pupil eccentricity was reduced by -39.56%; P<0.001.

CONCLUSION

Cataract extraction surgery appears to affect pupil size and shape, possibly in correlation to AC depth increase. This novel investigation based on digital analysis of Scheimpflug imaging data suggests that the cataract postoperative photopic pupil is reduced and more circular. These changes appear to be more significant with increasing patient age.

Retrospective evaluation of the influence of pupil size on visual acuity after KAMRA inlay implantation

PURPOSE

To investigate the influence of pupil size on visual acuity after KAMRA inlay (AcuFocus, Inc., Irvine, CA) implantation.

METHODS

Five hundred eighty-four presbyopic eyes of 584 patients who underwent LASIK were evaluated. Uncorrected near visual acuity (UNVA), uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and corrected near visual acuity (CNVA) were measured. Two groups were classified: small pupil (pupil diameter < 6 mm) and large pupil (pupil diameter ≥ 6 mm) for both mesopic (pupil diameter < 4 mm) and photopic (pupil diameter ≥ 4 mm) pupil size parameters. The follow-up period was 6 months.

RESULTS

There were no significant differences in UNVA (P = .98) and CNVA (P = .16) between the mesopic pupil size groups; however, there were significant differences in UDVA (P = .023) and CDVA (P = .039). There was a weak correlation between pupil size and UDVA of the large mesopic pupil size group (rs = 0.129, P = .04). There were no significant differences in UNVA (P = .78), CNVA (P = .92), UDVA (P = .19), and CDVA (P = .60) for the photopic pupil size groups.

CONCLUSIONS

Pupil size does not have an influence on the resultant visual acuity after KAMRA inlay implantation. No correlation was found between preoperative and postoperative pupil size and visual acuity for the mesopic pupil groups.

Age-related changes in accommodation measured with a double-pass system

PURPOSE

To measure the accommodative response in a wide age range population using the retinal image quality assessments provided by a double-pass system.

METHODS

The accommodative response was measured using a custom-built double-pass setup in 84 patients from 15 to 55 years of age. Patients were classified in four groups (A: 15-25 year old; B: 26-35; C: 36-45; D: 46-55). Accommodation was stimulated from 0 to 5 dioptres (D) with the push up method using an open field fixation test. The total accommodative response in the stimulated range, the accommodative stimulus-response curve, the slope and the progression of optical quality with accommodation were measured.

RESULTS

The total accommodation obtained in groups A and B was high, with a mean value of 4 D or higher, whereas values in older individuals were significantly lower. The accommodative stimulus-response curve and the slope were also high with a sudden decrease in patients over 35 years of age. The optical quality of the eye during accommodation did not change significantly.

CONCLUSIONS

Participants aged 15-35 years showed a good accommodative response. Thereafter, a significant decrease of the response in the total accommodation, stimulus response curve and slope was observed. The younger groups showed a larger accommodative response than previously published.

Changes in accommodative responses with multifocal contact lenses: a pilot study

PURPOSE

To evaluate induced changes in pupil and accommodative response for different accommodative stimuli with three different multifocal contact lenses (CLs).

METHODS

Accommodative and pupil responses with three aspheric multifocal CLs of simultaneous focus center near (PureVision Low Add, PureVision High Add and Focus Progressives) for two accommodative stimuli of -2.5 and -4.00 D were recorded in 10 young subjects. Accommodative response, peak velocity, and time constant of accommodation and pupil constriction were assessed. The measurements were evaluated in all the participants with distance-single vision CLs and with the three multifocal CLs. The monocular measurements were performed in a random sequence for each participant. All parameters were measured with a Hartmann-Shack aberrometer (IRX-3; Imagine Eyes, Orsay, France).

RESULTS

Differences were not found in accommodation response for both accommodative stimuli studied between the single vision lens and the three different multifocal CLs (p > 0.05 for both stimuli). For the 2.5 D stimulus, significant differences were not found in peak velocity and time constant between the single vision lens and the three different multifocal CLs (p > 0.05 for all situations); in amplitude of pupil constriction, differences were only found for the situation with PureVision High Add, where the value was lower than the single vision lens (p = 0.015). For the 4.00 D stimulus, differences with single vision lens in peak of velocity and time constant were only found with PureVision Low Add, where the peak velocity value was higher and the time constant was lower (p = 0.024 and p = 0.032 for peak of velocity and time constant, respectively); for amplitude of pupil constriction differences were not found (p > 0.05).

CONCLUSIONS

Data obtained in this pilot study suggest that in young observers, the multifocal CLs studied do not induce large changes in accommodative system compared with the single vision lens.

A multimeasure approach to investigating affective appraisal of social information in Williams syndrome

People with Williams syndrome (WS) have been consistently described as showing heightened sociability, gregariousness, and interest in people, in conjunction with an uneven cognitive profile and mild to moderate intellectual or learning disability. To explore the mechanisms underlying this unusual social-behavioral phenotype, we investigated whether individuals with WS show an atypical appraisal style and autonomic responsiveness to emotionally laden images with social or nonsocial content. Adolescents and adults with WS were compared to chronological age-matched and nonverbal mental age-matched groups in their responses to positive and negative images with or without social content, using measures of self-selected viewing time (SSVT), autonomic arousal reflected in pupil dilation measures, and likeability ratings. The participants with WS looked significantly longer at the social images compared to images without social content and had reduced arousal to the negative social images compared to the control groups. In contrast to the comparison groups, the explicit ratings of likeability in the WS group did not correlate with their SSVT; instead, they reflected an appraisal style of more extreme ratings. This distinctive pattern of viewing interest, likeability ratings, and autonomic arousal to images with social content in the WS group suggests that their heightened social drive may be related to atypical functioning of reward-related brain systems reflected in SSVT and autonomic reactivity measures, but not in explicit ratings.

Pupil responses to near visual demand during human visual development

Pupil responses of adults to near visual demands are well characterized but those of typically developing infants and children are not. This study determined the following pupil characteristics of infants, children and adults using a PowerRefractor (25 Hz): i) binocular and monocular responses to a cartoon movie that ramped between 80 and 33 cm (20 infants, 20 2-4-yr-olds and 20 adults participated) ii) binocular and monocular response threshold for 0.1 Hz sinusoidal stimuli of 0.25 D, 0.5 D or 0.75 D amplitude (33 infants and 8 adults participated) iii) steady-state stability of pupil responses at 80 cms (8 infants and 8 adults participated). The change in pupil diameter with viewing distance (Δpd) was significantly smaller in infants and 2-4-yr-olds than in adults (p < 0.001) and significantly smaller under monocular than binocular conditions (p<0.001). The 0.75 D sinusoidal stimulus elicited a significant binocular pupillary response in infants and a significant binocular and monocular pupillary response in adults. Steady-state pupillary fluctuations were similar in infants and adults (p = 0.25). The results suggest that the contribution of pupil size to changes in retinal image quality when tracking slow moving objects may be smaller during development than in adulthood. Smaller monocular Δpd reflects the importance of binocular cues in driving near-pupillary responses.

Inherent ocular spherical aberration and multifocal contact lens optical performance

PURPOSE

The role of inherent spherical aberration (SA) in the optical performance of presbyopic eyes corrected with simultaneous vision multifocal contact lenses was investigated.

METHODS

Presbyopic schematic eyes were modeled with partial accommodative function to represent 45- and 55-year olds and were further classified into five categories based on their magnitude of inherent SA. Two representative ametropic models of each category were corrected with four multifocal contact lens iterations. High-add designs were used to correct 55-year olds, whereas low-add designs served 45-year ones. The overall performances were gauged in terms of visual Strehl ratio and area under through-focus modulation transfer function.

RESULTS

The root mean square error of higher order aberrations of the eye and correcting lens combination were significantly different (p < 0.05) within the five inherent SA models, for all pupils and accommodative states. Area under through-focus modulation transfer function at all three spatial frequencies tested was found to be significantly different (p < 0.05) within the five SA models. Visual Strehl ratio measures were also different but statistically insignificant. Eyes having the same refractive prescriptions but diverse levels of inherent SA perform differently even when corrected with identical multifocal designs, and the performance is dependent on pupil size and level of residual accommodation. Overall, the distinct performances within the five SA models were optically relevant for pupils ∼4 mm and greater. Among the designs investigated, the low-add multizone iteration demonstrated performance relatively independent of the inherent SA because of the favorable interactions of defocus with primary, secondary, and tertiary SA.

CONCLUSIONS

These findings confirm that the coupling of ocular SA and correcting lens aberrations contributes to the multifocal functionality.

Static and dynamic accommodation measured using the WAM-5500 Autorefractor

PURPOSE

This study was undertaken to compare static and dynamic accommodation measurements using the Grand Seiko WR-5500 (WAM) in young, phakic subjects.

METHODS

Fifteen subjects, aged 20 to 28 years (23.8 ± 0.58 years; mean ± SD years) participated. Accommodation was stimulated with printed text presented at various distances. In static mode, three measurements were taken for each stimulus amplitude. In dynamic mode, 5-Hz recordings were started, and subjects alternately looked through a transparent near chart and focused on a letter chart at 6 m for 5 seconds and then focused on the near letter chart for 5 seconds for a total of 30 seconds. After smoothing the raw data, the highest three individual values recorded in each 5-s interval of focusing at near were averaged for each stimulus amplitude. Analysis of variance and Bland-Altman analysis were used to compare the static and dynamic measurements. A calibration was performed with +3.00 to -10.00 D trial lenses behind an infrared filter, in 1.00 D steps in 5 of the 15 subjects.

RESULTS

Stimulus-response graphs from static and dynamic modes were not significantly different in the lower stimulus range (<5.00 D, p = 0.93), but differed significantly for the higher stimulus amplitudes (p = 0.0027). One of the 15 subjects showed a significant difference between the static and dynamic modes. Corresponding pupil diameter could be recorded along with the accommodation responses for the subjects, and pupil diameter decreased with increasing stimulus demand. Calibration curves for static and dynamic measurements were not significantly different from the 1:1 line or from each other (p = 0.32).

CONCLUSIONS

Slight differences between the dynamically and statically recorded response amplitudes were identified. This is attributed to differences in the accommodative responses in this population and not to the instrument performance. Dynamic measurement of accommodation and pupil constriction potentially provides additional useful information on the accommodative response other than simply the response amplitude.

Disorders of the pupil

Pupil size is determined by the interaction of the parasympathetic and the sympathetic nervous system. The parasympathetic system conducts the light reaction with its major center in the dorsal midbrain. The sympathetic nervous system acts either directly on the dilator muscle (peripherally) or centrally by inhibiting the Edinger-Westphal nucleus. Psychosensory reactions are transmitted via the sympathetic system. The afferent input of the light reflex system in humans is characteristically wired, allowing a detailed analysis of a lesion of the afferent input. Even in humans a subgroup of ganglion cells containing melansopsin plays an important role as a light sensor for the pupillary system. To diagnose normal pupillary function, pupils need to be isocoric and react bilaterally equally to light. Anisocoria indicates a problem of the efferent pupillary pathway. Pupillary disorders may involve the afferent pathways (relative afferent pupillary defect) or the efferent pathways. Physiological anisocoria is a harmless condition that has to be distinguished from Horner's syndrome. In this case pharmacological testing with cocaine eye-drops is helpful. Disorders of the parasympathetic system will impair the light response. They include dorsal midbrain syndrome, third-nerve palsy, and tonic pupil. Tonic pupils are mainly idiopathic and do not need imaging. Disorders of the iris, including application of cholinergic agents, need also to be considered in impaired pupillary light reaction.

Comparison of the ocular wavefront aberration between pharmacologically-induced and stimulus-driven accommodation

PURPOSE

To compare the ocular wavefront aberration between pharmacologically- and stimulus-driven accommodation in phakic eyes of young subjects.

METHODS

The aberration structure of the tested eye when accommodating was measured using the Complete Ophthalmic Analysis System (COAS; AMO WaveFront Sciences, Albuquerque, NM, USA). It was used in conjunction with a purposely-modified Badal optometer to allow blur-driven accommodation to be stimulated by a high contrast letter E with a vergence range between +0.84 D and -8.00 D. Pharmacological accommodation was induced with one drop of pilocarpine 4%. Data from six subjects (age range: 23-36 years) with dark irides were collected.

RESULTS

No correlation was found between the maximal levels of accommodative response achieved with an 8 D blur-driven stimulus and pharmacological stimulation. Pharmacological accommodation varied considerably among subjects: maximum accommodation, achieved within 38-85 min following application of pilocarpine, ranged from 2.7 D to 10.0 D. Furthermore, although the changes of spherical aberration and coma as a function of accommodation were indistinguishable between the two methods for low levels of response, a characteristic break in the pattern of aberration occurred at higher levels of pilocarpine-induced accommodation. This probably resulted from differences in the time course of biometric changes occurring with the two methods.

CONCLUSION

Measuring the pilocarpine-induced accommodative response at only one time point after its application may lead to misleading results. The considerable inter-individual differences in the time course of drug-induced accommodative response and its magnitude may lead to overestimation or underestimation of the corresponding amplitude of normal, blur-driven accommodation. Stimulating accommodation by topical application of pilocarpine is inappropriate for evaluating the efficacy of 'accommodating' IOLs.

Pupil sizes in different Japanese age groups and the implications for intraocular lens choice

PURPOSE

To observe pupil sizes with near and distance vision under different lighting conditions in different Japanese age groups.

SETTING

Department of Ophthalmology, Tokyo Dental College Suidobashi Hospital, Tokyo, Japan.

METHODS

Using an open view-type infrared video pupillometer, the horizontal and vertical pupil sizes were measured prospectively with subjects gazing at 30 cm or 3 m targets under photopic (illumination 500 lux) and mesopic (illumination 5 lux) conditions. The results were analyzed by age, and the benefits with various multifocal IOLs were evaluated.

RESULTS

The study comprised 140 eyes (70 subjects; 14 to 94 years). The mean +/- standard deviations of photopic vertical pupil sizes when gazing far/near decreased from 3.77 +/- 0.23/3.50 +/- 0.33 mm (<20 years) to 2.20 +/- 0.30/1.95 +/- 0.20 mm (over 80 years), with pupil sizes stabilizing after 60 years. The mesopic vertical pupil sizes when gazing far/near decreased from 6.35 +/- 0.11/6.27 +/- 0.14 mm (<20 years) to 3.42 +/- 0.30/3.21 +/- 0.28 mm (over 80 years). The pupil sizes decreased with age until 60 years and stabilized (1-way analysis of variance, P<.05). Fewer than 50% of subjects over 60 years of age had pupil sizes conducive to the near zone of refractive multifocal intraocular lenses.

CONCLUSION

Photopic and scotopic pupil sizes decreased with age up to 60 years. The pupil was smaller when gazing at a near target than previously reported.

Neuroadaptation of presbyopia-correcting intraocular lenses

PURPOSE OF REVIEW

Advances in the design of intraocular lenses give options to patients for some return to the optical accommodation needed to focus on objects at different distances. Technology is only improving these options for presbyopic-correcting intraocular lenses. Surgeons must consider the possible neuroadaptation abilities in patients that may help in the success of using these lenses.

RECENT FINDINGS

The hierarchy of the visual system allows two disparate retinal images to combine to form a single picture with depth. Attempts to correct presbyopia with intraocular lenses add complexity to the pathway with the possible introduction of monovision or intraocular rivalry. The neuroadaptation involved in successful use of these lenses has not been study but has been well established in other neurologic processing.

SUMMARY

Understanding what patient selection factors are important for neuroadaptation may contribute to outcome success.